A U.S. general has accused Tehran of sending rockets to Shi'ite groups fighting Iraq's government and U.S. forces in Iraq. VOA's Jim Randle Reports from Baghdad.

The U.S. military spokesman, Major General Kevin Bergner, said U.S. experts have gathered considerable evidence a rocket that hit the American military headquarters in Iraq Tuesday came from Iranian sources.

The rocket hit Camp Victory, near Baghdad's International Airport, killing one person and wounding 11. The general said the rocket was launched from an area of western Baghdad that is a stronghold of the Mahdi Army militia led by radical Shi'ite cleric Moqtada al-Sadr.

"The attack used a 240-millimeter rocket, which is a weapon that these groups have received from Iranian sources in the past and recently used in other attacks against coalition forces," he explained.

The general said fragments of the rocket that survived the explosion had colors and markings consistent with Iranian origin.

General Bergner's comments follow similar allegations from other top U.S. officials who have accused Iran of supplying deadly roadside bombs used against U.S. troops.

On Wednesday, the top U.S. commander in Iraq, General David Petraeus, said there is hard evidence of Iranian efforts to establish a permanent militia presence in Iraq and that the United States had captured an official of the Iran-backed Hezbollah militia in southern Iraq.

Iranian President Mahmoud Ahmadinejad has rejected allegations that his nation is interfering in Iraq.

But Thursday General Bergner repeated Washington's contention that Iran is supplying money, training, and arms to forces opposing the Iraqi government and U.S. troops.

He confirmed news reports that coalition forces are opening a base along the Iran-Iraq border to stop the flow of weapons and other aid to such groups.

"So we have looked at places where the positioning of coalition forces would better work with Iraqi forces and the government of Iraq in interdicting that flow," he added.

But Bergner said news reports gave a mistaken impression that there is a "strategic commitment" to a new base in Iraq. He said it is just an "adjustment" of existing forces.

Elsewhere, a roadside bomb killed a key Sunni Arab sheikh cooperating in the U.S.-led fight against al-Qaida in Iraq. Iraqi police said Abdul Sattar Abu Risha died in an attack near his home in western al-Anbar province.

Abu Risha was among a group of tribal leaders who met with President Bush during his visit to Iraq last week. No group claimed responsibility for the assassination, but suspicion fell on al-Qaida in Iraq, which U.S. officials say has suffered devastating setbacks in Anbar because of Abu Risha and his fellow sheiks.

Meanwhile, the U.S. military says it plans to release between 50 and 80 Iraqi detainees per day during the Muslim holy month of Ramadan. In a note to reporters, officials said the releases would be based on an impartial judicial review, and require those released to promise to obey the law.

The military statement said the program is a joint venture with the Iraqi government and that the first group of detainees is being freed Thursday.